Ted blabs excuses about Karen being his first love, and the tough year he's had, and then deflects the conversation back to Marshall and his stunning lack of pants at the office. Barney starts chanting for the pants story, but Marshall insists there is no story. So? We flash back to the no-story story. Marshall calls Lily at work and explains his need of pants, which has been compounded by a mustard incident that took out his backup pair. [Note that the pregnant Alyson Hannigan, who's been sitting down this entire episode, is now standing behind a massive, stomach-level globe. Also, note that I'm wondering how an elementary school teacher has the free time to go home and bring Marshall a pair of pants. I can't imagine she has a free period. - Zach] Flash forward to MacLaren's. Lily's not letting Ted distract them from the Karen story and insists he finish. When he insists there was just one kiss... "in the restaurant." Lily calls him out on his qualifier, which is a great thing about old friendships, isn't it? The good ones are so onto your B.S., you shouldn't even bother. Flash back to Ted's apartment -- he and Karen enter, in the dark, joined at the lips, tearing off each other's clothes. Flash forward to MacLaren's. Everyone's disgusted, even Barney, who moans, "Ted how could you?" Of course he also reaches behind Robin's back to give Ted a high five, so maybe he's less committed to his condemnation of Ted than are the others. Lily comments that although Marshall forgot to bring his pants to work today, Ted's still the stupidest person at the table.
Ted takes off the gloves. "Okay Lily, let's be honest. We both know your real motivation here. You hate Karen because she...lingered." Lily calls him a son of a bitch, and we flash back to Ted and Marshall's dorm room. Lily's painting a nude portrait of Marshall when Karen barges in. She apologizes and heads right back out, although she takes her time taking in the Marshall merchandise. She then comes back in again, using a critique of Lily's color palette (it's derivative of early Van Gogh) as her excuse, but her eyes never leave Marshall. Flash forward to MacLaren's. Lily says, "Cheat on Ted, criticize my painting? Whatever. That's your business. But I catch you peeping on my man's junk and you linger? You gots to get got." Robin agrees. "The game is the game." Marshall steps to Karen's defense. "I had just worked out." Ted asks why Lily was painting Marshall nude, anyhow. She says, "Because, he ate my bowl of fruit," because this show wants you, needs you and loves you with all its heart, and just can't stop giving these little continuity-gasms. Let the haters say what they may. We know the truth. Lily's less philosophical. "The point is, Karen is a dirty lingerer, and you cannot bring her back into our lives."